The aim of this study is to investigate the cognitive, affective, and medical effects of restoring circulating levels of DHEA to approximately the high-normal range of young adults in psychiatrically and medically healthy men and women between the ages of 56 and 85 years whose serum DHEA-S levels are in the lower 50% for their age group. The study is a double-blind crossover administration trial. Subjects will receive placebo or DHEA (45 or 90 mg) for 6 months, no drug for 1 month, and the other treatment (DHEA or placebo) for 6 months. At the beginning and end of each 6-month administration period, subjects will undergo mood and memory assessments, a blood draw, and a variety of medical tests. We hope to use the GCRC for the following procedures: phlebotomy; urine sample collection, and analysis of urinary bone products; subject instruction in maintaining a food-choice diary; provision of standard meals; and possibly other medical tests or subject instructions.